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1.
bioRxiv ; 2023 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-38168302

RESUMEN

Background: The inability to evaluate host immunity in a rapid quantitative manner in patients with sepsis has severely hampered development of novel immune therapies. The ELISpot assay is a functional bioassay that measures the number of cytokine-secreting cells and the relative amount of cytokine produced at the single-cell level. A key advantage of ELISpot is its excellent dynamic range enabling a more precise quantifiable assessment of host immunity. Herein, we tested the hypothesis on whether the ELISpot assay can detect dynamic changes in both innate and adaptive immunity as they often occur during sepsis. We also tested whether ELISpot could detect the effect of immune drug therapies to modulate innate and adaptive immunity. Methods: Mice were made septic using sublethal cecal ligation and puncture (CLP). Blood and spleens were harvested serially and ex vivo IFN-γ and TNF-α production were compared by ELISpot and ELISA. The capability of ELISpot to detect changes in innate and adaptive immunity due to in vivo immune therapy with dexamethasone, IL-7, and arginine was also evaluated. Results: ELISpot confirmed a decreased innate and adaptive immunity responsiveness during sepsis progression. More importantly, ELISpot was also able to detect changes in adaptive and innate immunity in response to immune-modulatory reagents, for example dexamethasone, arginine, and IL-7 in a readily quantifiable manner, as predicted by the reagents known mechanisms of action. ELISpot and ELISA results tended to parallel one another although some differences were noted. Conclusion: ELISpot offers a unique capability to assess the functional status of both adaptive and innate immunity over time. The results presented herein demonstrate that ELISpot can also be used to detect and follow the in vivo effects of drugs to ameliorate sepsis-induced immune dysfunction. This capability would be a major advance in guiding new immune therapies in sepsis.

2.
Environ Health Perspect ; 109 Suppl 1: 79-91, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11250808

RESUMEN

Alterations in nervous system function after exposure to a developmental neurotoxicant may be identified and characterized using neurobehavioral methods. A number of methods can evaluate alterations in sensory, motor, and cognitive functions in laboratory animals exposed to toxicants during nervous system development. Fundamental issues underlying proper use and interpretation of these methods include a) consideration of the scientific goal in experimental design, b) selection of an appropriate animal model, c) expertise of the investigator, d) adequate statistical analysis, and e) proper data interpretation. Strengths and weaknesses of the assessment methods include sensitivity, selectivity, practicality, and variability. Research could improve current behavioral methods by providing a better understanding of the relationship between alterations in motor function and changes in the underlying structure of these systems. Research is also needed to develop simple and sensitive assays for use in screening assessments of sensory and cognitive function. Assessment methods are being developed to examine other nervous system functions, including social behavior, autonomic processes, and biologic rhythms. Social behaviors are modified by many classes of developmental neurotoxicants and hormonally active compounds that may act either through neuroendocrine mechanisms or by directly influencing brain morphology or neurochemistry. Autonomic and thermoregulatory functions have been the province of physiologists and neurobiologists rather than toxicologists, but this may change as developmental neurotoxicology progresses and toxicologists apply techniques developed by other disciplines to examine changes in function after toxicant exposure.


Asunto(s)
Conducta Animal/efectos de los fármacos , Sistema Nervioso/efectos de los fármacos , Sistema Nervioso/crecimiento & desarrollo , Animales , Animales de Laboratorio , Cognición/efectos de los fármacos , Humanos , Ratones , Actividad Motora/efectos de los fármacos , Ratas , Medición de Riesgo , Conducta Social , Pruebas de Toxicidad/métodos
3.
Behav Neurosci ; 102(5): 706-13, 1988 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3196440

RESUMEN

The purpose of this study was to characterize the ontogeny of the acoustic startle response (ASR) and response sensitization to background noise in preweanling rats. Animals were tested daily from 11 to 21 days of age using one of four sets of background white noise levels [45-80 dB(A)]. With constant low-level (45 dB, SPL) background noise, response latency decreased steadily with age, whereas both response incidence and amplitude increased nonmonotonically with age. Two approaches were used to examine the ontogeny of sensitization to background noise: The first compared the ASR of animals tested at 75 dB background noise with ones tested at 45 dB; the second compared the ASR of animals tested at three background levels (30 dB range) within the test session. Sensitization was not evident before 15-16 days of age. By comparing these results with the results from naive animals, it was found that daily test experience does not alter ASR amplitude, latency, incidence, or the development of sensitization.


Asunto(s)
Envejecimiento/fisiología , Vías Auditivas/fisiología , Ruido , Reflejo de Sobresalto/fisiología , Umbral Sensorial , Estimulación Acústica , Animales , Ratas , Tiempo de Reacción/fisiología
4.
Toxicol Sci ; 41(1): 8-20, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9520337

RESUMEN

The Food Quality Protection Act of 1996 (FQPA) requires the EPA to consider "available information concerning the cumulative effects of such residues and other substances that have a common mechanism of toxicity ... in establishing, modifying, leaving in effect, or revoking a tolerance for a pesticide chemical residue." This directive raises a number of scientific questions to be answered before the FQPA can be implemented. Among these questions is: What constitutes a common mechanism of toxicity? The ILSI Risk Science Institute (RSI) convened a group of experts to examine this and other scientific questions using the organophosphorus (OP) pesticides as the case study. OP pesticides share some characteristics attributed to compounds that act by a common mechanism, but produce a variety of clinical signs of toxicity not identical for all OP pesticides. The Working Group generated a testable hypothesis, anticholinesterase OP pesticides act by a common mechanism of toxicity, and generated alternative hypotheses that, if true, would cause rejection of the initial hypothesis and provide criteria for subgrouping OP compounds. Some of the alternative hypotheses were rejected outright and the rest were not supported by adequate data. The Working Group concluded that OP pesticides act by a common mechanism of toxicity if they inhibit acetylcholinesterase by phosphorylation and elicit any spectrum of cholinergic effects. An approach similar to that developed for OP pesticides could be used to determine if other classes or groups of pesticides that share structural and toxicological characteristics act by a common mechanism of toxicity or by distinct mechanisms.


Asunto(s)
Insecticidas/toxicidad , Animales , Inhibidores de la Colinesterasa/toxicidad , Interacciones Farmacológicas , Humanos , Compuestos Organofosforados/toxicidad , Medición de Riesgo
5.
Toxicology ; 142(1): 29-39, 1999 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-10647916

RESUMEN

The carcinogenic potential of 1-(1-methyl-propoxycarbonyl)-2-(2-hydroxyethyl)-piperidine (KBR 3023), a prospective new insect repellent intended for human use, was studied in mice using the dermal route of application. Relying upon the toxicology profile that emerged in the subchronic rat bioassay that was conducted using dermally applied dosages of 0, 80, 200, 500, and 1000 mg KBR 3023/kg body weight per day, it was determined, in concert with the EPA, that dermally applied dosages of 0, 50, 100, or 200 mg KBR 3023/kg body weight per day would be used in the conduct of all definitive forms of subchronic, chronic, and lifetime descriptive testing performed with the chemical. Using this testing approach, the specific results of this 18-month study are as follows. All in-life parameters, which included body weight, food consumption, clinical observations, survival, and hematology were unaffected by exposure to KBR 3023. Similarly, postmortem analyses, which included organ weights and gross pathology, and histopathology were also unchanged following exposure to KBR 3023. No evidence of a compound-induced neoplasia was suggested in this bioassay.


Asunto(s)
Repelentes de Insectos/toxicidad , Piperidinas/toxicidad , Piel/efectos de los fármacos , Administración Cutánea , Animales , Bioensayo , Peso Corporal/efectos de los fármacos , Pruebas de Carcinogenicidad , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/efectos de los fármacos , Ojo/efectos de los fármacos , Ojo/patología , Femenino , Masculino , Ratones , Ratones Endogámicos ICR , Tamaño de los Órganos/efectos de los fármacos , Piel/patología
6.
Toxicology ; 142(1): 41-56, 1999 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-10647917

RESUMEN

The chronic toxicology and carcinogenic potential of 1-(1-methyl-propoxycarbonyl)-2-(2-hydroxyethyl)-piperidine (KBR 3023), a prospective new insect repellent intended for human use, was studied in rats using the dermal route of application. Relying upon the toxicology profile that emerged in the subchronic rat bioassay that was conducted using dermally applied dosages of 0, 80, 200, 500 and 1000 mg KBR 3023/kg body wt/day, it was determined, in concert with the Environmental Protection Agency (EPA), that dermally applied dosages of 0, 50, 100 or 200 mg KBR 3023/kg body wt/day would be used in the conduction of all definitive forms of subchronic, chronic, and lifetime descriptive testing performed with the chemical. Using this testing approach, the specific results of this 2-year study are as follows. All in-life parameters, which included body weight, food consumption, clinical observations, survival, ophthalmology, clinical chemistry, hematology, and urinalysis, were unaffected by exposure to KBR 3023. Similarly, postmortem analyses, which included organ weights and gross pathology, were also unchanged following exposure to KBR 3023. Histopathology at the dose site/skin was characterized by a pattern of acanthosis and/or hyperkeratosis across all doses in 1- and 2-year rats. Beyond the dosing site, cystic degeneration of the liver was described in 2-year 200-mg KBR 3023/kg body wt/day males. No other compound-related non-dosing site lesion was identified at any dose tested. No evidence of a compound-induced neoplasia was suggested in this bioassay.


Asunto(s)
Repelentes de Insectos/toxicidad , Piperidinas/toxicidad , Piel/efectos de los fármacos , Administración Cutánea , Animales , Bioensayo , Peso Corporal/efectos de los fármacos , Pruebas de Carcinogenicidad , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Ingestión de Alimentos/efectos de los fármacos , Ojo/efectos de los fármacos , Ojo/patología , Femenino , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Tamaño de los Órganos/efectos de los fármacos , Piperidinas/administración & dosificación , Ratas , Ratas Sprague-Dawley , Piel/patología
7.
Neurotoxicology ; 21(1-2): 57-63, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10794385

RESUMEN

Evidence that neonates are more sensitive than adults to organophosphorus (OP) and pyrethroid insecticides is largely based on studies that compare toxicity at acute lethal doses. Under such circumstances, the greater susceptibility of the neonate appears to be due to limited metabolic capacity rather than an inherent difference in the sensitivity of target sites. For purposes of risk assessment with food-use pesticides, the more relevant issue is whether the neonate is more sensitive than the adult to lower levels of exposure, approximating levels used to establish acceptable residue limits (tolerances) on various food products. If infants and children are not more sensitive to environmentally-relevant levels of exposure, then the existing tolerances for dietary exposure will provide adequate protection. If, on the other hand, they may be more sensitive, then additional studies with young animals or an additional uncertainty factor may be needed for added protection. This paper examines two sets of studies that address this issue. The first involves multi-generation reproduction studies with rats that were treated with OP insecticides (coumaphos, fenamiphos, tribufos, trichlorfon, or oxydemeton-methyl) through the diet and examined for effects, including cholinesterase (ChE) inhibition. The second involves rats that were treated by gavage with an acute dose of a pyrethroid (cismethrin, permethrin, deltamethrin or cypermethrin) to establish relative sensitivity to either a lethal dose or to a low, behaviorally-active dose. The results with the OP insecticides support ChE inhibition as the most sensitive measure of exposure and the critical effect (i.e., the lowest NOEL) for each study was based on ChE inhibition in the adult. The magnitude of ChE inhibition in pups (measured on postnatal day (PND) 4 and 21) was consistently less than for adults at a given dietary level. For the representative Type I pyrethroids, there was no evidence that pups are more sensitive than adults at any dose level. For both Type II pyrethroids, young rats were considerably more sensitive than adults to a lethal dose but not to lower doses. Levels of deltamethrin in whole-brain tissue support kinetics as the basis for the greater sensitivity of young rats to a lethal dose, with the immature systems involved with detoxification being overwhelmed at such high dose levels. These findings indicate that young animals are not more sensitive than adults to lower doses of OP or pyrethroid insecticides. This outcome supports the conclusion that infants and children are protected by existing tolerances, without the need for an additional uncertainty factor.


Asunto(s)
Envejecimiento/fisiología , Insecticidas/toxicidad , Compuestos Organofosforados , Piretrinas/toxicidad , Estimulación Acústica , Animales , Encéfalo/efectos de los fármacos , Encéfalo/enzimología , Femenino , Dosificación Letal Mediana , Masculino , Nivel sin Efectos Adversos Observados , Ratas , Ratas Long-Evans , Reflejo de Sobresalto/efectos de los fármacos , Caracteres Sexuales
8.
Reprod Toxicol ; 14(2): 135-46, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10825677

RESUMEN

1,6-Hexamethylene diisocyanate (HDI), a chemical widely used in commercial polyurethane products, was evaluated in a combined reproductive/developmental/neurotoxicity study. Sprague-Dawley rats (n = 120; 15 per sex/dose group) were administered via whole-body inhalation exposure either 0, 0.005, 0.05, or 0.3 ppm HDI for 6 h/day during a 14-day premating phase, up to a 14-day mating phase, and a 21-day gestation phase. The dams and their litters were maintained for a 4-day lactation phase during which exposure to HDI was discontinued. Neurobehavioral testing (automated measures of activity and a functional observational battery) was conducted before exposure, after the premating phase, and before termination. Body weight and clinical observations were recorded throughout the study. Terminal examinations included a gross necropsy, hematology, and clinical chemistry. Tissues retained for microscopic examination included the reproductive organs, neural tissues, nasal turbinates (multiple sections), trachea, larynx, and lung. The animals were also evaluated for effects on mating, fertility, gestation length, litter size, pup sex ratio, and pup viability. In the 0.300 ppm dose group a statistically significant decrease in body weight was observed in the females on day 4 of the study. Also observed at this dose level, in both males and females, were microscopic alterations in the nasal cavity, primarily epithelial hyperplasia, squamous metaplasia, chronic-active inflammation, and more seriously, degeneration of the olfactory epithelium. Similar microscopic effects were also observed, albeit to a lesser extent, in the males and females of the 0.05 ppm dose level. No histopathologic effects were observed in the 0.005 ppm dose level. No effects on any reproductive or neurotoxicologic parameters, hematology, clinical chemistry, or any effects on pup growth and development were observed at any exposure level.


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Animales Recién Nacidos/crecimiento & desarrollo , Encéfalo/efectos de los fármacos , Cianatos/toxicidad , Efectos Tardíos de la Exposición Prenatal , Reproducción/efectos de los fármacos , Administración por Inhalación , Animales , Conducta Animal/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Femenino , Gónadas/efectos de los fármacos , Gónadas/patología , Isocianatos , Lactancia , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Tamaño de los Órganos/efectos de los fármacos , Embarazo , Ratas , Ratas Sprague-Dawley , Pruebas de Toxicidad/métodos , Cornetes Nasales/efectos de los fármacos , Cornetes Nasales/patología
9.
Pharmacol Biochem Behav ; 33(2): 415-22, 1989 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2530591

RESUMEN

The involvement of serotonin (5-HT) in modulating the acoustic startle response (ASR) is well established in adult rats, but 5-HT involvement during the preweaning period, when 5-HT neurons undergo extensive development, has not previously been described. Three 5-HT receptor subtypes are reported to modulate the ASR in adult rats: 5-HT1A and 5-HT2 receptor agonists facilitate the ASR, whereas 5-HT1B agonists decrease the response. In the present study, the effects of 5-HT agonists and generalized 5-HT depletion on the ASR were studied in preweanling animals, using independent groups of Long-Evans rats tested on postnatal day (PND) 13, 17 and 21. 8-Hydroxy-2-(di-n-propylamino) tetralin (8OHDPAT, 62-1000 micrograms/kg), a 5-HT1A receptor agonist, and 5-methoxy-N,N-dimethyl tryptamine (MeODMT, 2-4 mg/kg), a nonselective 5-HT agonist, had no effect on PND 13 and then increased the ASR on PND 17 and 21. The 5-HT2 receptor antagonists cyproheptadine (5 mg/kg) and ketanserin (5 mg/kg) blocked the effect of MeODMT at both ages, providing some evidence that MeODMT increased the ASR through 5-HT2 receptors. 1-(m-Chlorophenyl) piperazine (mCPP, 1-5 mg/kg), a 5-HT1B agonist, had no effect on ASR amplitude on PND 13 or 17 and then produced a dose-related decrease in the response on PND 21. Generalized depletion of 5-HT by 80-90% in whole-brain and spinal cord, using p-chlorophenylalanine (PCPA, 300 mg/kg 24 hr prior to testing), did not alter ASR amplitude at any age.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Animales Lactantes/fisiología , Reflejo de Sobresalto/fisiología , Serotonina/fisiología , 8-Hidroxi-2-(di-n-propilamino)tetralin , Estimulación Acústica , Factores de Edad , Animales , Química Encefálica , Ciproheptadina/farmacología , Dopamina/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Fenclonina/farmacología , Ketanserina/farmacología , Masculino , Metoxidimetiltriptaminas/farmacología , Norepinefrina/análisis , Piperazinas/farmacología , Ratas , Reflejo de Sobresalto/efectos de los fármacos , Serotonina/análisis , Tetrahidronaftalenos/farmacología
10.
Nurs Clin North Am ; 24(4): 881-9, 1989 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-2587392

RESUMEN

Liver transplantation celebrated its twenty-fifth anniversary in 1988. However, only in the last decade has it been accepted as a viable treatment alternative for patients with end-stage liver disease. There currently are over 70 centers in the United States with liver transplant programs. Over 1500 transplants were performed in 1988, and there were 644 people awaiting suitable liver donors, with an average of 150 to 200 patients added to the list each month. This growth has resulted from many factors, including improved operative techniques and anesthetic management, immunosuppressive therapies, and improvements in donor recovery, which has served to increase the acceptable organs available for transplantation. The future of liver transplantation, however, may be somewhat uncertain. Will the cost of patient care continue to be supported by the economy? The goal of liver transplantation is simple: to provide the patient with a better quality and longer life. The question remains, is this a goal that society will deem financially feasible?


Asunto(s)
Hepatopatías/cirugía , Trasplante de Hígado/enfermería , Adaptación Psicológica , Humanos , Inmunosupresores/uso terapéutico , Trasplante de Hígado/economía , Trasplante de Hígado/psicología , Educación del Paciente como Asunto , Complicaciones Posoperatorias/enfermería , Obtención de Tejidos y Órganos
11.
Appl Clin Inform ; 4(2): 170-84, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23874356

RESUMEN

BACKGROUND: Increased usage of MedlinePlus by Spanish-speakers was observed after introduction of MedlinePlus in Spanish. This probably reflects increased usage of MEDLINE and PubMed by those with greater fluency in the language in which it is presented; but this has never been demonstrated in English speakers. Evidence that lack of English fluency deters international healthcare personnel from using PubMed could support the use of multi-language search tools like Babel-MeSH. OBJECTIVES: This study aims to measure the effects of language fluency and other socioeconomic factors on PubMed MEDLINE and MedlinePlus access by international users. METHODS: We retrospectively reviewed server pageviews of PubMed and MedlinePlus from various periods of time, and analyzed them against country statistics on language fluency, GDP, literacy rate, Internet usage, medical schools, and physicians per capita, to determine whether they were associated. RESULTS: We found fluency in English to be positively associated with pageviews of PubMed and MedlinePlus in countries with high literacy rates. Spanish was generally found to be positively associated with pageviews of MedlinePlus en Español. The other parameters also showed varying degrees of association with pageviews. CONCLUSIONS: After adjusting for the other factors investigated in this study, language fluency was a consistently significant predictor of the use of PubMed, MedlinePlus English and MedlinePlus en Español. This study may support the need for multi-language search tools and may increase access of health information resources from non-English speaking countries.


Asunto(s)
Barreras de Comunicación , Lenguaje , MedlinePlus/estadística & datos numéricos , PubMed/estadística & datos numéricos , Producto Interno Bruto/estadística & datos numéricos , Humanos , Internacionalidad , Internet/estadística & datos numéricos , Médicos/provisión & distribución , Facultades de Medicina/provisión & distribución , Factores Socioeconómicos
12.
Appl Clin Inform ; 3(3): 326-33, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23646080

RESUMEN

BACKGROUND: Smartphones are increasingly important for clinical decision support, but smartphone and Internet use are limited by cost or coverage in many settings. txt2MEDLINE provides access to published medical evidence by text messaging. Previous studies have evaluated this approach, but we found no comparisons with other tools in this format. OBJECTIVES: To compare txt2MEDLINE with other databases for answering clinical queries by text messaging in low-resource settings. METHODS: Using varied formats, we searched txt2MEDLINE and five other search portals (askMEDLINE, Cochrane, DynaMed, PubMed PICO, and UpToDate) to develop optimal strategies for each. We then searched each database again with five benchmark queries, using the customized search-optimization formats. We truncated the results to less than 480 characters each to simulate delivering them to a maximum of three text messages. Clinicians with practice experience in low-resource areas scored the results on a 5-point Likert scale. RESULTS: Median scores and standard deviations from 17 reviewers were: txt2M2MEDLINE, 3.2±0.82 (control); askMEDLINE, 3.2±0.90 (p = 0.918); Cochrane, 3.8±0.58 (p = 0.073); DynaMed, 3.6±0.65 (p = 0.105); PubMed PICO, 3.6±0.82 (p = 0.005); and UpToDate, 4.0±0.52 (p = 0.002). Our sample size was sufficiently powered to find differences of 1.0 point. CONCLUSIONS: Comparing several possible sources for texting-based clinical-decision-support information, our results did not demonstrate one-point differences in usefulness on a scale of 1 to 5. PubMed PICO and UpToDate were significantly better than txt2MEDLINE, but with relatively small improvements in Likert score (0.4 and 0.8, respectively). In a texting-only setting, txt2MEDLINE is comparable to simulated alternatives based on established reference sources.


Asunto(s)
Teléfono Celular , Sistemas de Apoyo a Decisiones Clínicas/normas , MEDLINE , Informática Médica/métodos , PubMed , Envío de Mensajes de Texto , Informática Médica/normas , Motor de Búsqueda/métodos , Motor de Búsqueda/estadística & datos numéricos
13.
Reprod Toxicol ; 34(3): 331-9, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22677474

RESUMEN

The extended one-generation reproduction toxicity study (OECD 443, adopted 28-July-2011) produces more information with fewer animals than the two-generation study (OECD 416), by including F1 neurotoxicity and immunotoxicity assessments, and omitting an F2 generation if there are no relevant F1 findings. This saves >1000 animals per compound. Feasibility studies based on draft OECD443 were conducted in industrial GLP laboratories in Europe and USA, using vinclozolin, methimazole and lead acetate. A fourth study was conducted with 2,4-dichlorophenoxyacetic acid (2,4-D) in response to a regulatory request for reproduction and developmental neurotoxicity data. The studies effectively profiled vinclozolin as an anti-androgenic developmental toxicant, methimazole as a developmental anti-thyroid agent, and lead acetate as a systemic and developmental toxicant. The 2,4-D study demonstrated the value of toxicokinetic data in dose setting and data interpretation. These results illustrate the variety of reproductive and developmental endpoints which can be captured in this complex but manageable study design. Time constraints for triggering further (F2) testing are summarized.


Asunto(s)
Alternativas al Uso de Animales , Sustancias Peligrosas/toxicidad , Reproducción/efectos de los fármacos , Pruebas de Toxicidad/métodos , Ácido 2,4-Diclorofenoxiacético/toxicidad , Antagonistas de Andrógenos/toxicidad , Animales , Antitiroideos/toxicidad , Femenino , Sistema Inmunológico/efectos de los fármacos , Masculino , Metimazol/toxicidad , Síndromes de Neurotoxicidad/etiología , Compuestos Organometálicos/toxicidad , Oxazoles/toxicidad , Ratas , Ratas Sprague-Dawley , Ratas Wistar
16.
Toxicol Appl Pharmacol ; 78(3): 412-20, 1985 May.
Artículo en Inglés | MEDLINE | ID: mdl-2413587

RESUMEN

Chick embryos were treated with tri-o-cresyl phosphate (TOCP) or leptophos, organophosphorus compounds that cause delayed neurotoxicity. Embryos received either TOCP (62 or 250 microliter/kg egg) or leptophos (125 to 750 mg/kg egg) Day 14 of incubation and were examined after hatching for nerve damage. The high doses caused high embryo mortality. Chicks which survived the high doses were grossly ataxic from hatching until the study was ended at 3 weeks posthatching. On Posthatching Day 2, many degenerating nerve fibers were observed in the profundus/superficialis peroneus nerve in chicks surviving the high doses. TOCP-treated chicks were followed in detail for neuromuscular changes. Twenty days after hatching there were fewer large nerve fibers in the distal ischiadic nerve compared with controls and the largest nerve fibers were absent in the peroneus profundus nerve. Consistent with the evidence of denervation there was increased terminal branching of motor axons in femoral (sartorius) and tibial (external gastrocnemius and peroneus longus) leg muscles. The leg nerves of chicks treated with the low dose of TOCP did not show either an excessive number of degenerating nerve fibers or a detectable loss of large nerve fibers. However, terminal branching of motor axons was increased in the external gastrocnemius and peroneus longus muscles of 5- and 15-day-old chicks, followed by recovery by Day 25. The evidence is interpreted as a distal axonopathy in chicks treated with TOCP during late embryonic development.


Asunto(s)
Cresoles/toxicidad , Insecticidas/toxicidad , Leptofos/toxicidad , Fibras Nerviosas/efectos de los fármacos , Enfermedades Neuromusculares/inducido químicamente , Tritolilfosfatos/toxicidad , Animales , Ataxia/inducido químicamente , Embrión de Pollo , Pollos , Diarrea/inducido químicamente , Fibras Nerviosas/patología
17.
Toxicol Appl Pharmacol ; 79(1): 39-46, 1985 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-2413588

RESUMEN

Chick embryos were injected on incubation Day 14 with 62 microliter of triorthocresyl phosphate (TOCP)/kg egg. Muscles of the leg were examined from 5 to 25 days after hatching. The sartorius from the thigh and the external gastrocnemius and peroneus longus from the tibial leg region were compared for muscle fiber size and end-plate length over this period. Treated chicks showed no acute toxic effects or overt ataxia and were equal in body weight to controls. At 5, 15, and 25 days after hatching, morphologic alterations consistent with denervation were detected. Muscle fibers were smaller than controls on Day 5 and were hypertrophic on Days 15 and 25. On Day 5 growth of fibers was retarded, an effect consistent with denervation, and the subsequent hypertrophy is predicted as compensation for denervated fibers. Small end plates were seen on Day 15, characteristic of end plates that were delayed in development by denervation. Each of these differences was greater in the tibial muscles than in the more proximally located sartorius. This is consistent with a distal neuropathy, such as that caused by TOCP in adult hens. Some recovery was apparent at the low dose 25 days after hatching. It is suggested that this resulted from reinnervation by repaired axons. This study of the myoneural apparatus and muscle fiber response to TOCP adds evidence to the possibility that the developing chick embryo may develop delayed neuropathy from organophosphorus compounds which produce this effect in adult hens.


Asunto(s)
Cresoles/toxicidad , Músculos/efectos de los fármacos , Tritolilfosfatos/toxicidad , Animales , Embrión de Pollo , Miembro Posterior , Placa Motora/efectos de los fármacos , Placa Motora/ultraestructura , Músculos/inervación , Músculos/patología , Coloración y Etiquetado
18.
J Toxicol Environ Health ; 21(4): 445-53, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-3599089

RESUMEN

Chick embryos were treated during late embryonic development with tri-ortho-cresyl phosphate (TOCP), an organophosphate compound that causes delayed neurotoxicity in humans and some other species. Embryos were treated on incubation d 14 with either 62 or 250 microliters TOCP/kg egg. The higher dose reduced the number hatched, and signs of cholinergic toxicity were apparent in the newly hatched chick. All chicks that survived this dose were unable to stand. Recovery from the cholinergic effects occurred within a few days after hatching, but the chicks remained severely ataxic through 3 wk of observation. The mortality of embryos treated with 62 microliters TOCP/kg egg was not higher than that of controls, and young chicks showed no overt signs of cholinergic toxicity or ataxia. Motor impairment was detected by measuring gait parameters. These chicks had a short stride and walked with a more open angle of foot placement. These are adjustments in gait that provide a more steady base of support. The change in gait developed over a 3-wk period after hatching. The hindlimb motor impairment detected at both doses is consistent with neuropathy such as is seen in the adult chicken. The value of gait analysis is the ability to quantify effects that are not apparent by simple observation.


Asunto(s)
Ataxia/inducido químicamente , Cresoles/toxicidad , Tritolilfosfatos/toxicidad , Animales , Peso Corporal/efectos de los fármacos , Embrión de Pollo , Marcha , Pierna/efectos de los fármacos
19.
Vet Hum Toxicol ; 37(6): 521-7, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8588286

RESUMEN

A minimally-invasive method of quantitative electroencephalography (qEEG) that requires no anesthetics and parallels techniques of naturalistic stimulation was developed and validated for regulatory testing of drugs and chemicals in rats. Male and female Fischer 344 rats were utilized in a randomized-block design to measure qEEG target parameters associated with a range of cholinesterase inhibition. For this study, physostigmine was administered ip at doses of 0.05, 0.2 or 1.0 mg/kg, resulting in average cholinesterase inhibition in plasma (28, 38 and 70%), erythrocytes (19, 24 and 36%), and brain (2, 10 and 31%) which correlated well with increased total power and amplitude changes. Additional treatment-related effects consisted of decreased relative alpha and beta, increased relative delta, and a left-shift in the spectral-edge frequency. In a second study, male and female Sprague-Dawley rats were utilized in a treatment-by-subjects design to determine qEEG target parameter changes due to the M2 autoreceptor agonist oxotremorine. Repeated incremental doses (0.05, 0.1, 0.2 mg/kg; ip) of oxotremorine resulted in increased beta contribution, a right-shift in the spectral-edge frequency and decreased alpha contribution. These qEEG results with physostigmine and oxotremorine correlate well with receptor-specific and general muscarinic effects, making it a reliable contribution to analysis of agonist and antagonist effects of cholinergic compounds.


Asunto(s)
Encéfalo/efectos de los fármacos , Inhibidores de la Colinesterasa/toxicidad , Agonistas Muscarínicos/toxicidad , Oxotremorina/toxicidad , Fisostigmina/toxicidad , Ritmo alfa/efectos de los fármacos , Animales , Ritmo beta/efectos de los fármacos , Encéfalo/enzimología , Inhibidores de la Colinesterasa/administración & dosificación , Inhibidores de la Colinesterasa/metabolismo , Colinesterasas/sangre , Simulación por Computador , Ritmo Delta/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Electroencefalografía , Eritrocitos/efectos de los fármacos , Eritrocitos/enzimología , Femenino , Inyecciones Intraperitoneales , Masculino , Agonistas Muscarínicos/administración & dosificación , Agonistas Muscarínicos/metabolismo , Oxotremorina/administración & dosificación , Oxotremorina/metabolismo , Fisostigmina/administración & dosificación , Fisostigmina/metabolismo , Distribución Aleatoria , Ratas , Ratas Endogámicas F344 , Ratas Sprague-Dawley
20.
Vet Hum Toxicol ; 38(1): 1-7, 1996 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8825739

RESUMEN

A minimally-invasive method of quantitative electroencephalography (qEEG) that requires no anesthetics and parallels techniques of naturalistic stimulation was developed and validated for regulatory testing of drugs and chemicals in rats. Male and female Fischer 344 rats were utilized in a randomized-block design to measure qEEG target parameters associated with a range of cholinesterase inhibition. For this study, physostigmine was administered ip at doses of 0.05, 0.2 or 1.0 mg/kg, resulting in average cholinesterase inhibition in plasma (28, 38 and 70%), erythrocytes (19, 24 and 36%), and brain (2, 10 and 31%) which correlated well with increased total power and amplitude changes. Additional treatment-related effects consisted of decreased relative alpha and beta, increased relative delta, and a left-shift in the spectral-edge frequency. In a second study, male and female Sprague-Dawley rats were utilized in a treatment-by-subjects design to determine qEEG target parameter changes due to the M2 autoreceptor agonist oxotremorine. Repeated incremental doses (0.05, 0.1, 0.2 mg/kg; ip) of oxotremorine resulted in increased beta contribution, a right-shift in the spectral-edge frequency and decreased alpha contribution. These qEEG results with physostigmine and oxotremorine correlate well with receptor-specific and general muscarinic effects, making it a reliable contribution to analysis of agonist and antagonist effects of cholinergic compounds.


Asunto(s)
Encéfalo/efectos de los fármacos , Inhibidores de la Colinesterasa/toxicidad , Evaluación Preclínica de Medicamentos , Agonistas Muscarínicos/toxicidad , Oxotremorina/toxicidad , Fisostigmina/toxicidad , Análisis de Varianza , Animales , Encéfalo/enzimología , Inhibidores de la Colinesterasa/administración & dosificación , Colinesterasas/sangre , Relación Dosis-Respuesta a Droga , Electroencefalografía/efectos de los fármacos , Electroencefalografía/métodos , Eritrocitos/efectos de los fármacos , Eritrocitos/enzimología , Femenino , Inyecciones Intraperitoneales , Masculino , Agonistas Muscarínicos/administración & dosificación , Oxotremorina/administración & dosificación , Fisostigmina/administración & dosificación , Distribución Aleatoria , Ratas , Ratas Endogámicas F344 , Ratas Sprague-Dawley
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